Control of deflection in rolling mills and the like



1967 TADEUSZ SENDZIMIR 3,355,924

CONTROL OF DEFLECTION IN ROLLING MILLS AND THE LIKE Filed July 10, 1963 4 Sheets-Sheet 1 Fig. l

INVENTOR. TADEUSZ SENDZIMIR,

ATTORNEYS.

JIM/1% 1967 TADEUSZ SENDZIMIR 3,355,

, CONTROL OF DEFLECTION IN ROLLING MILLS AND THE LIKE 4 Sheets$heet Filed July 10, 1963 INVENTOR TADEUSZ SENDZIMIQ,

ATTORNEYS,

5, 1967 TADEUSZ SENDZIMIR 3,355,924-

CONTROL OF DEFLECTION IN RGLLING MILLS AND THE LIKE Filed July 10, 1965 4 Sheets-Sheet 5 INVENTOR TADEUSZ SENDZIMIR,

Dec. 5, 1967 TADEUSZ SENDZIMIR CONTROL OF DEFLECTION IN ROLLING MILLS AND THE LIKE 4 Sheets-Sheet Filed July 10, 1963 ZNVENTOR TADEUSZ SENDZIMIR,

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ATTORN EY,$

United States Patent 3,355,924 CONTROL OF DEFLECTION IN ROLLING MILLS AND THE LIKE Tadeusz Sendzimir, T. Sendzimir, Inc., Waterbury, Conn. 06712 Filed July 10, 1963, Ser. No. 294,048 11 Claims. (Cl. 72241) This invention has to do with solving the problems of deflection in heavy metal structures subjected to great stresses. The invention will be described in connection with mills for rolling metal strips and the like, it being understood that the principles of the invention may be applied to other structures. It is well known that in the rolling of metal sheets or strip the forces required to produce the desired elongation and diminution in thickness of the metal are very great and act primarily in a direction tending to separate the working rolls, for which reason they are ordinarily referred to as roll separating forces. It is also well known that the roll separating forces may be diminished by the use of working rolls of smaller diameter; but small working rolls are comparatively easily deflected by the forces involved.

Therefore in rolling mills having working rolls of comparatively small diameter it is usual to provide some backing means tending to offset the deflection of the working rolls. These means may comprise other rolls of very much larger diameter as in Well known 4-high mills or in cluster mills.

The second expedient employed to minimize the effect of working roll deflection lies in grinding the surfaces of the working rolls in such a way as to produce a crown, i.e., to provide working rolls which are thicker at the centers of their working surfaces than at the ends thereof. The crowning of the working rolls is effective primarily only under one set of rolling conditions, i.e., where the roll separating forces are of a certain value and remain constant. It will be understood that crowning of the working rolls which over-compensates for roll deflection under any given circumstances will result in the production of strip with a full center portion, while under-compensation has the opposite effect.

Improvements have been made in rolling mills designed to do flat rolling. The Sendzimir cold rolling mill, features of which are described in numerous patents of the present inventor, contemplates a housing characterized by beams extending longitudinally of the working rolls. The working rolls, which are usually supported by one or more sets of intermediate rolls, find their final support in casters mounted in saddles on the beams. The working rolls therefore are supported throughout their effective lengths, and to all intents and purposes are prevented from deflecting under the roll separating forces excepting to the extent that the beams themselves deflect. The beams can be made quite heavy and rigid; and mills of the character to which reference has been made (see US. Patents 2,479,974 and 2,566,679, for example), have succeeded in accomplishing flat rolling with accuracy theretofore unknown. For example, in the Sendzimir cold strip mills it has been possible to keep deflections under 1/ 10,000 of an inch where the stresses on the beams are kept below about 1000 p.s.i., the beams themselves being steel castings having an elastic limit of over 40,000 p.s.i.

Moreover, as set forth in US. Patent 2,776,586 and elsewhere, it is possible so to design the mill housings including the beams, that deflections occurring at the central portions thereof will be in large part compensated by permitting deflections in the beams nearer the ends of the effective portions of the working rolls.

The very great accuracy of such rolling mills tends to diminish where for any reason the roll separating forces become excessive, or where one encounters a situation of 3,355,924 Patented Dec. 5, 1967 diminishing returns in an endeavor to make the beams more rigid. Where this is the case an increase in the crosssectional dimensions of the beams is inadequate to improve their rigidity to the desired extent. Hitherto, in mechanical structures operating under load, where deflection is detrimental, but where for reasons of geometry or technology it is not possible or advisable to attain rigidity by merely increasing dimensions, the prior art has generally sought to add another structure of steel having greater rigidity against which the first mentioned structure can be supported. This is not always completely effective because, since most of the added rigidifying structures are made of steel, the modulus of elasticity is not a matter of choice. It is an object of the present invention to provide means and a structure wherein the avoidance of deflection is not dependent on the rigidity of supporting structures alone.

Thus it is an object of the invention. to provide against deflection in structures where rigidity alone will not adequately eliminate deflection.

It is an object of the invention to provide structures in which tendencies toward deflection can be compensated over a very wide range without necessarily increasing the size and weight of rigidifying elements such as beams, rolls, or the like.

It is an object of the invention to provide antideflection means which are selective in their action and which can be applied to supporting elements subject to deflection at differing positions and with differing effectiveness depend: ing upon the locus and magnitude of the forces tending to produce deflection.

It is an object of the invention to provide means of the character hereinabove referred to which will permit the accurate operation of rolling instrumentalities over a wide range of changing conditions, and which also are adjustable to meet changing conditions as they arise, even in the course of a single rolling operation.

An object of one aspect of the invention is the provision of means which compensate for or minimize deflection under load and also means which indicate the extent of any deflection remaining or the forces required to overcome it.

These and other objects of the invention which will be set forth hereinafter or will be apparent to one skilled in the art upon reading these specifications are ac'complished by that structure and arrangement of parts of which certain exemplary embodiments will now be described. Reference is made to the accompanying drawings, wherein:

FIGURE 1 is a vertical sectional view, take on the line 1-1 of FIGURE 2, of astructure subject to deflection, compensating means for that deflection, and gauging means for showing the extent of deflection or compensation.

FIGURE 2 is an end elevation of the same apparatus, with parts in section on the line 22 of FIGURE 1.

FIGURE 2a is a partial schematic representation of one means for measuring deflection and controlling the response to same.

FIGURE 3 is a central vertical sectional view of a 4-high mill arranged for the practice of the invention;

FIGURE 4 is an elevational view of one of the backing element cores.

FIGURE 5 is a fragmentary central vertical sectional view similar to FIGURE 3, showing the coactionof a modified backing element core and its sleeve.

FIGURE 6 is a front elevational view of certain elements of a beam-backed mill (with parts in section) showing one structure for and mode of practicing the invention.

FIGURE 7 is a transverse cross-section taken at the center of the structure of FIGURE 6.

FIGURE 8 is an elevational view, similar to FIGURE 6, of a modified form of the apparatus.

The present invention is a improvement over means hitherto employed for preventing detrimental deflections, and is especially valuable in mechanisms where the shape or form of the structure is such that reliance on the rigidity alone of some element or elements will not be sufliciently effective. By consequence it is of value in structures in which increases in the size or cross-sectional depth of an element or elements encounters the law of diminishing returns.

Briefly, in the practice of the invention the structure designed to prevent deflection is divided into two coacting parts, a first part which tends to resist deflecting stresses by reason of a high rigidity, and a second structure acting upon the first structure to support it, where the second structure can itself be subject to deflection but will still minimize deflection in the first structure. While in many assemblies the first structure will be much more rigid than the second and will take the load directly (being subject to low unit stresses) and the outer structure may be subject to as high unit stresses as the material will withstand and will therefore show deflection, the arrangement of parts may be reversed as will hereinafter appear. Moreover, it does not constitute a limitation on the invention that either of the two structures must necessarily be substantially more rigid than the other. In any event however, there will be a transfer of load from one of the structures to the other so that under the particular condition of use of the apparatus, one of the structures may be maintained in a substantially undeflected condition, or in a condition of controlled deflection.

One form of the invention is diagrammatically illustrated in FIGURES 1 and 2. Here a frame 1 is shown as having beam-like portions 2 and 3 connected by portions 4 and 5 at their ends. The portions 2, 3, 4 and 5 surround a central hollow space 6 within which stresses are exerted on the beams in the direction of the arrow 7. The beams 2 and 3 may be rigidified by providing them with a substantial vertical depth.

For illustrative purposes, let use assume that the element 1 is a one-piece housing for a cold rolling mill, that the total length of the aperture or space 6 is about 120 inches, and that a material is being rolled within the space 6 by means of rolling instrumentalities ultimately supported by the beams 2 and 3. Assume further that a material 100 inches wide is being rolled in the mill. Under these circumstances the forces exerted on the beams 2 and 3 as indicated by the arrow 7 may well be of the order of tons per linear inch over a total length of 100 inches. It is difficult to design a structure 1, using a steel casting of reasonably heavy section (which casting itself may Weigh around 150 tons) in such a way that the beam portions 2 and 3 would deflect at their centers under the assumed load less than about 0.0008 to 0.001 inch. Moreover because of the law of diminishing returns, an increase in the weight of the housing 1 to say 200 tons, would probably result in only a slight decrease or no decrease at all in the deflection under load.

Depending upon the kind of work to be performed by the .mill, deflections within the range set forth above, may be tolerable; but it should be pointed out first that if a range of deflections is selected as tolerable, the specific deflections will stay within the range only so long as the stresses do not exceed a certain limit. Second, a given range or" deflections may not be tolerable during variations in rolling procedure and especially when rolling wide sheet or strip material. The wider the material being rolled, the more certain it will be that deflections will cause the rolled product to be uneven in gauge and wavy. Corrective measures such as crowning the rolls are well known to be accurate only for one specific load; and an important part of the problem solved by this invention is the provision of means whereby deflection may be prevented, minimized, or held Within predetermined tolerable ranges entirely independently of the magnitude and disposition of the load.

To this end, a framework 8 is provided which, in the exemplary embodiment, consists of an upper beam assembly 9 and a lower beam assembly 10, the ends of the beam assemblies being connected together respectively by tension members 11 and 12. Between the upper beam assembly 9 and the upper beam 2 of the casting 1 there are shown a plurality of spaced hydraulically actuated pressure elements 13, 13a-13e. Similarly between the lower beam assembly 10 and the lower beam 3 is located a series of hydraulically actuated pressure elements 14, 14a-14e. These comprise cylinders mounted on the beam assemblies and having pistons, such as shown at 15, which engage the upper and lower beam assemblies at selected intervals. When the pressure elements are actuated, counterforces will be exerted upon the beams 2 and 3 which will tend to counteract the deflecting effects of the separating forces exerted in the direction 7. In exerting these counter-forces, it makes no difference whether the composite beams and 10 deflect, and it makes no difference Whether elongation occurs in the tension elements 11 and 12, so long as these respective deflections and elongations fall below the elastic limits of the materials of which the second framework 8 is made. This is because the pressures exerted by the pressure elements 13, 14, etc., will depend upon the fluid pressures maintained in the cylinders. It is well to actuate the cylinders separately, such as by control means indicated generally at 1311 and 14a, since the amount of actual deflection would vary along the lengths of the beams 2 and 3, so that the structure hereinabove described permits the exertion of counter forces upon the beams at relatively closely spaced intervals and in direct proportion to the actual deflections which would occur in the absence of the counter-forces. Not only do the roll separating forces tend to produce differences in deflection across the mill when rolling full width stock, but when the mill is used to roll narrower strip it will be evident that the forces will be characterized by further unequal distribution across the mill, and that the compensation will be different in the two cases.

In the exemplary embodiment the beams 2 and 3 are made so as to be quite resistive to deflecting forces since the auxiliary structure or framework designated by the numeral 8 serves to suppress the general tendencies of the beams to flex. In particular the beams of the structure 1 must be sufficiently rigid that flexure between the points of action of the pistons 15 will be negligible.

Still assuming that the first structure 1 is part of a rolling mill, and that the cylinders 13, 14, etc. are separately actuatable, the adjustment of the pressure exerted by an individual cylinder may be accomplished by observing and measuring the piece being rolled, and then controlling the pressure in the several cylinders to give a flat product, and one devoid of camber and the like.

However, FIGURES 1 and 2 also illustrate a means whereby deflection can be measured and adjustment effected in accordance with such measurements. The beams 2 and 3 are provided with relatively small longitudinal bores 16 and 17. A frame element 18 has upper and lower legs 19 and 20 extending through these bores. In the upper bore there may be elements 21 which will support the frame 18 at the ends of the beam 2 in such a way that the frame legs 19 and 20 do not normally contact the beams 2 and 3.

Between the upper frame leg 19 and the floor of the bore 16 a series of gauges 22 are provided, and a similar series of gauges 23 is located between the frame leg 20 and the upper surface of the bore 17. These gauges are preferably located opposite the pistons 15 of the pressure cylinders. The gauges are of known character serving to indicate variations in the distance between the frame and the floor and ceiling respectively of the bores 16 and 17. The floor and ceiling of the respective bores may be lined if desired with a harder metal facing as indicated at 24.

The gauges, whether operating by pressure displacement or electrically, will have leads brought out in such a way that the gauges may be individually read. The frame 18 is not subjected to the deflecting stresses on the beams excepting insofar as a minute fraction of these stresses may be transmitted through the gauges 22 and 23. The rigidity of the frame 18 will be such as to withstand these stresses so that the gauges will give a definitive measurement of the actual deflections of the beams 2 and 3.

The indications derived from the gauges 22 and 23 can be used in various ways. They can be made visible on meters 22a and 23a such as shown in FIGURE 2a, so that the mill operator can use these indications in manually adjusting the hydraulic pressures in the several cylinders 13, 14, etc. Again, automatically acting connections (see FIGURE 2a) between the gauges 22 and 23- and valves controlling the hydraulic cylinders may be provided. In the practice of the extremely delicate art of accurately rolling flat metal strips, automatic adjustment means plus provision for manual adjustment when required, are preferred. Manual adjustment may be accomplished on the basis of indications derived from the gauges, or from indications derived from instruments acting upon the product itself after rolling, or both.

It will be understood that various arrangements of the points or areas contacted by the pistons 15 of the pressure cylinders may be employed, depending in large part upon the nature of the mill. It will also be understood that in lieu of hydraulic cylinders other pressure exerting elements such as screws, wedges, pressure cushions and the like may be employed. Some of these will be described hereinafter.

FIGURES 3, 4 and 5 illustrate the principles of the invention applied to mills which for exemplary purposes may be visualized as 4-high mills. Such a mill, as shown in FIGURE 3, may comprise end housings 25 and 26 of ordinary configuration for such mills. A work piece 27 is shown as being reduced between working rolls 28 and 29. These working rolls have necks 30, 31, 32 and 33, which are mounted in bearings 34, 35, 36 and 37, which bearings are normally made slidable in the windows of the mill frame members as conventional in the art. The working rolls will normally have coupling means 38 and 39 by which the working rolls may be connected to a mill driving motor through a conventional pinion stand.

The backing means of the mill of FIGURE 3 comprises upper and lower backing assemblies each consisting of two parts, viz, an inner backing roll 40 or 41, these rolls being solid excepting for certain perforations hereinafter described, and an outer sleeve 42 or 43. The last mentioned sleeve elements are in direct contact with the Working rolls 28 and 29.

Screw-down means will he provided for such mills; and these will take various forms which may include conventional hand or motor operated screws threaded in the mill housings and engaging bearing assemblies for the backing rolls. By way of an exemplary showing neck portions 44, 45, 46 and 47 of the solid backing rolls are shown mounted eccentrically in circular bearing elements 48, 49, 50 and 51. These bearing elements are rotatably mounted in holes in the mill housings and are provided with worm gears 52, 53, 54 and 55. A skilled worker in the art will understand that by reason of the eccentric mounting aforesaid, screw-down in the mill may be affected by the rotation of worms (not shown), which engage the worm gears. The solid rolls 40 and 41 are kept from rotation by brackets 56 and 57 afiixed respectively to their necks and to the mill housing 25. The sleeves 42 and 43 are held against axial movement by the eccentric bearing elements 48, 49, 50 and 51, and are free to rotate with the working rolls 28 and 29.

As indicated in FIG. 4, the solid roll 40 is divided on its u 1 1 der side into a series of areas marked 58 by grooves 59. The areas need not be of the same size but are preferably arranged symmetrically. The grooves 59, which both surround the assembly of areas and extend between adjacent areas are fitted with expansible seals 61. Holes 60 are provided, at least one for each area. These holes either connect the several areas with a longitudinal perforation 61a in the roll 40, or preferably are individually connected to separate pressure pipes 62 which extend through the bore 61a and, externally of the mill, are individually connected with valved sources of fluid pressure (not shown).

The lower backing roll 41 is provided with similar configurations and adjuncts as will be evident from FIG. 3.

The sleeve members 42 and 43 are loosely held on the backing rolls 40 and 41, i.e., in a manner which will permit deflection to occur; but the expansion seals 61 remain at all times in contact with adjacent surfaces of the sleeves despite sleeve rotation. As a consequence, the introduction of fluid under pressure into the various areas 58 will separate those portions of the sleeves which contact the working rolls from the backing rolls 40 and 41 by greater or lesser distances depending upon the actual pressures applied, and despite some leakage past the seals.

The strip 27 being rolled is preferably maintained in a symmetrical position in the mill. It becomes possible then to make overall adjustments in the pressures on areas 58 lying to the right and left of the center line of the mill and in this way control the general behavior of the strip in the mill. Afterwards, from data obtained from the strip itself, adjustment of the pressures in individual areas can be practiced to correct errors in rolling as will now be readily understood.

The backing rolls 40 and 41 are themselves rigid bodies capable of substantially reducing the deflections of the Working rolls which would otherwise occur. The sleeves 42 and 43 also have a considerable rigidity; but the combination as described in connection with FIGURES 3, 4 and 5, enables deflections of the Working rolls to be controlled far more accurately than would be the case with solid backing rolls of equivalent diameter. In a sense, the arrangement taught herein serves to control the effective shape of the backing means as it bears against the working rolls. In very wide (4-high) mills, it is not possible to provide single :backing rolls of such very great diameters as will preclude some flexing thereof under normal rolling procedures. For example, in mills having a width suitable for rolling strip about inches Wide, it is not pra-cticable to make solid backing rolls greater in diameter than about 65 or 70 inches; and such diameter will provide rolls having ,too great a flexibility. Crowning the working rolls or the backing rolls will effect compensation for deflection only under a given load. In the assembly of this invention compensation may be attained over a very wide range of operating loads even though both the solid backing rolls 40 and 41 and the sleeve elements 42 and 43 do not have individual rigidities suflicient for the purpose.

Those skilled in the art have a wide choice of known hydraulic circuits for the establishment. and maintenance of controlled pressures Within the areas 58, which in most cases will lie between 2000 and 10,000 p.s.i. The use of oil in this connection, besides giving control of the deflection of the working rolls along the lines of contact between them and the backing assemblies, also establishes an oil film of adequate depth to provide free rotation for the sleeves 42 and 43. For example, a typical known hydraulic circuit (not shown) would include a fixed delivery high pressure oil pump for each area 58, capable of delivering a quantity of oil in excess of the leakage past the expansible seals aforesaid, each such pump being equipped with a bypass valve enabling the pressure to be set at a desired value. The number andaxial lengths of the areas 58 will depend on the diameters of the elements involved, i.e., the relative rigidities of the rolls and sleeves and the rolling program of the mill. The circumferential lengths of the areas 58 will depend on the thickness of the sleeves as well as the diameters of the assemblies. An increase in the areas of the divisions 58 will change the effective by: d raulic pressure. Also, too great a circumferential extent 7 may, if the thicknesses of the sleeves 42 and 43 is limited, introduce certain bending stresses.

A modification of structure may be noted in FIGURE in that the bearing elements 63 and 64 accept necks 65 and 66 on the sleeve 42, the neck 66 being provided additionally with means 67 for connection to a source of power. In this instance the solid roll 40 is held against rotation by a somewhat modified bracket 68.

In structures of the character described in connection With FIGS. 3, 4 and 5, the solid rolls 40 and 41 will generally be subject to some deflection. This is of little consequence with respect to the accuracy of control of the deflection of the working rolls, providing that the material of which the solid backing rolls are made, will withstand the stresses imposed by the roll separating force, and providing that the deflections are not so large as to make an effective seal impracticable. The problem may be ameliorated in wide mills by crowning the solid rolls 40 and 41 within the sleeve members 42 and 43. The crown should be proportioned to the average mill load, at which seals will work under ideal conditions. An advantage of the structure is that the seals provide a range of deflections above and below the median, throughout which range the mill will still function satisfactorily as to the seals and can still be adjusted so as to compensate for deflections of the working rolls which would otherwise occur.

FIGURES 6 and 7 show the application of the principle of this invention to beam-backed mills. Such mills are disclosed in Patent No. 2,776,586 and others, and they generally consist of a housing having rigid means parallel to the working rolls. Such beams are indicated in the figures at 69 and 70. The beams are tied together at the ends of the housing by portions 71 and 72 which are usually, but not necessarily, parts of the same casting. Parallel channels 73 and 74 are machined in the facing surfaces of the beams, and serve to locate saddles 7 5 and 76 which in turn support caster elements 77 and 78. A rather simple type of such mill is illustrated in FIG. 7, wherein the working rolls 79 and 80 are shown as supported directly by the casters 77 and 78. In many such mills one or two or more sets of intermediate rolls will be located between the working rolls and the casters, which will be multiplied accordingly. In many such mills screw-down is accomplished by locating the casters eccentrically with respect to the saddles and then rotating the saddles, or by providing eccentric means in which the casters themselves are mounted; but this constitutes no limitation on the present invention.

The inherent rigidity of mill housings of the type just described is such that they are capable of supporting small diameter working rolls with a sufficiently low deflection to provide rolled strip up to about 60 inches wide. When the mill is constructed to handle still wider materials, it becomes increasingly difficult to design mill housings the deflections of which will be less than some specific figure, say 0.0005 inch. Sheer weight added by making the mill housings larger, is of little help.

In the practice of the present invention, extremely accurate results may be achieved in the following manner: the top and bottom faces of the housing beams 69 and 70 are so designed as to present relatively large flat areas which may be either round or rectangular or oval in configuration; and these areas are machined. An independent auxiliary structure 81 is provided comprising an upper beam element 82 and a lower beam element 83 lying respectively above and below the mill housing beams 69 and 70. The beams 82 and 83 are made wide enough to cover the aforesaid machined areas on the outer sides of the beams 69 and 70, and the beams 82 and 83 may be held together by four tie members, two of which are shown at 84 and 85 in FIG. 6. The tying members may extend, as shown, through vertical holes in the mill housing so that the parts may be held in accurate assembly.

Hydraulic seals indicated at 86 are disposed between the facing surfaces of the mill housing beams and the frame beams respectively, the seals running around close to the periphery of the machined areas so as to close off a pressure space indicated at 87. Hydraulic fluid may be intro: duced into the pressure spaces aforesaid, and the pressure of the fiuid can be so adjusted as to completely compensate for deflection of the housing beams 68 and 70, i.e., to keep these beams from deflecting. The pressure spaces 87 should be so designed as to cover in length a major part of the width of the strip to be rolled. The pressure can be so adjusted as to relieve the mill housing means of all bending and shearing stresses, if desired, although deflection of the beams 82 and 83 will occur.

As illustrated in FIGS. 6 and 7, each mill housing beam has one area only (as at 87) which will be subjected to the hydraulic pressure. In mills designed to roll strips of various widths it is desirable to subdivide the opposed machined surfaces of the mill housing beams and the beams 82 and 83 into smaller areas in a manner analogous to FIGURE 4, since on narrow widths the pressure will be concentrated more in the center of the beam of the mill. If the compensating counterpressure is so controlled by means including seals as to be limited to the same area, any deflection of the mill beams will be more accurately eliminated. It should be borne in mind, however, that the beams 67 and 70 of mills such as are disclosed in FIGS. 6 and 7, are inherently very rigid, and in most cases can withstand load differences due to variations in the width of the strips being rolled.

The practice of the invention is not limited to the use of hydraulic pressure means. As shown in FIG. 8, screwdown type elements 89 may be interposed between the mill housing beam 69 and the external beam 82. These mechanical pressure exerting elements may be provided with worm gears and operated either together or selectively by worms (not shown).

FIGURE 8 also illustrates the fact that it is not necessary to provide a complete external frame work. The beam 82 may be attached to the end portions 71 and 72 of the mill housing by tension studs 90 and 91 threaded directly into the mill housing. Although not shown in FIG. 8, it will be understood that a beam element 83 will be provided beneath the mill housing beam 70, may be provided with similar pressure exerting instrumentalities, and similarly attached to the end portions 71 and 72 of the mill housing.

Modifications may be made in the invention Without departing from the spirit of it. The invention having been described in certain exemplary embodiments, what is claimed as new and desired to be secured by Letters Patent is:

1. A method for diminishing the deflection of a pair of mutually opposed pressure bearing stationary beams of a mill housing used in rolling fiat articles which comprises providing one of a pair of cooperating parallel structures outside each of said beams, and interposing between each beam and its adjacent structure at least one pressure element capable of exerting a controlled force on said structure in a direction substantially opposite to the direction of deflection resulting from the rolling of said articles.

2. The process claimed in claim 1 wherein a plurality of pressure elements are interposed in spaced relationship between each said beam and its adjacent cooperating structure, and including the step of separately controlling the pressures exerted by said pressure elements, whereby in part at least to compensate for varying deflections of the said relatively rigid mechanical structure.

3. In a mechanical device the combination of a pair of mutually opposed relatively rigid structures subject to deflection by reason of separating forces exerted thereon, and means for diminishing said deflection comprising at least one stationary cooperating structure parallel to one of said structures, said latter structure being disposed near and spaced from one of said rigid structures, means fixing said structures against movements at their ends, and at least one pressure element interposed between each said rigid structure and said parallel structure adjacent thereto at the parts of said rigid structure subject to deflection, whereby to exert pressure upon said rigid structure at said parts in a direction opposite to the direction of the deflecting forces.

4. The structure cliamed in claim 3 including a plurality of pressure elements interposed between said rigid and cooperating parallel structures at selected intervals and means for independently controlling the pressure exerted by the individual pressure elements.

5. The structure claimed in claim 4 including a member related to the first mentioned relatively rigid structure and having deflection gauges interposed between it and the said structure whereby the degree of deflection of said structure at various parts thereof may be measured.

6. The structure claimed in claim 5 including connections between said deflection gauges and said pressure elements whereby the pressure exerted by said pressure elements is made responsive to the deflections measured by said deflection gauges.

7. The structure claimed in claim 3 wherein said cooperating parallel structure is a beam, and the ends of said beam are spaced in substantially a fixed relationship to the ends of said adjacent rigid structure.

8. The structure claimed in claim 7 wherein said pressure element is fluid activated.

9. The structure claimed in claim 7 wherein there are a pair of spaced and relatively rigid parallel beams, and wherein tension members connect the ends of said beams.

10. The structure claimed in claim 7, wherein said beam is tied at its ends to the ends of the adjacent rigid structure.

11. The structure claimed in claim 7 wherein said pressure element comprises mechanical means located at spaced intervals in the direction of the length of the beam.

References Cited UNITED STATES PATENTS 1,781,809 11/1930 Detwiler 72-243 X 1,910,158 5/1933 Frank 72-243 2,792,730 5/1957 Co ZZa -56 2,907,235 10/ 1959 Murakami 72-243 2,985,042 5/ 1961 Talbot 72-245 3,031,872 5/ 1962 Kiisters 72-245 3,076,360 2/ 1963 Sendzimir 72-243 X 3,169,423 2/1965 Sims 72-243 RICHARD J. HERBST, Primary Examiner.

C. H. HITTSON, A. RUDERMAN,

Assistant Examiners. 

3. IN A MECHANICAL DEVICE THE COMBINATION OF A PAIR OF MUTUALLY OPPOSED RELATIVELY RIGID STRUCTURES SUBJECT TO DEFLECTION BY REASON OF SEPARATING FORCES EXERTED THEREON, AND MEANS FOR DIMINISHING SAID DEFLECTION COMPRISING AT LEAST ONE STATIONARY COOPERATING STRUCTURE PARALLEL TO ONE OF SAID STRUCTURES, SAID LATTER STRUCTURE BEING DISPOSED NEAR AND SPACED FROM ONE OF SAID RIGID STRUCTURES, MEANS FIXING SAID STRUCTURES AGAINST MOVEMENTS AT THEIR ENDS, AND AT LEAST ONE PRESSURE ELEMENT INTERPOSED BETWEEN EACH SAID RIGID STRUCTURE AND SAID PARALLEL STRUCTURE ADJACENT THERETO AT THE PARTS OF SAID RIGID STRUCTURE SUBJECT TO DEFLECTION, WHEREBY TO EXERT PRESSURE UPON SAID RIGID STRUCTURE AT SAID PARTS IN A DIRECTION OPPOSITE TO THE DIRECTION OF THE DEFLECTING FORCES. 